Robotic surgical systems have been used in minimally invasive medical procedures. Some robotic surgical systems included a console supporting a robot arm, and at least one end effector such as forceps or a grasping tool that is mounted to the robot arm via a wrist assembly. During a medical procedure, the end effector and the wrist assembly were inserted into a small incision (via a cannula) or a natural orifice of a patient to position the end effector at a work site within the body of the patient.
Cables extended from the robot console, through the robot arm, and connected to the wrist assembly and/or end effector. In some instances, the cables were actuated by means of motors that were controlled by a processing system including a user interface for a surgeon or clinician to be able to control the robotic surgical system including the robot arm, the wrist assembly and/or the end effector.
In some instances, the wrist assembly provided three degrees of freedom for movement of the end effector through the use of three cables or cable pairs, one for each degree of freedom. For example, for grasping or cutting end effectors the wrist assembly provided the three degrees of freedom by allowing changes to a pitch, a yaw, and an opening and closing of the end effector.
As demand for smaller surgical tools increased, device manufacturers developed surgical tools such as grasping and cutting tools having smaller cross-sectional areas. These smaller cross-sectional areas reduced the total force that could be applied between two jaws at the end of the tools. Additionally, the use of three cables or cable pairs to provide three degrees of motion required a minimum cross-sectional area to implement and limit the ability to further reduce the cross sectional area of these tools. Finally, the force that was applied was not customizable to provide varying forces depending on the position of the jaws in relation to each other as the jaws are opened and closed.
There is a need for surgical tools having small cross-sectional areas that are able to provide high forces between end effector jaws, including customizable forces that vary depending on the position of the jaws in relation to each other.